The controls of an AR-15 are almost entirely on the lower receiver and included in a AR-15 lower parts kit. A lower parts kit is a wide variety of small parts that complete an 80 percent lower. This includes the fire control group I.E. trigger and associated parts. The magazine lock and release, as well as the bolt release. It is the heart and soul of your AR-15 build kit, and there are massive amounts of options for LPKs out there. So what’s best? Well, you need to consider a few points before making your choice.
Quality and Budget
What is the level of quality you are looking for? Personally, I start with mil spec as the base layer and work my way up. I accept nothing less than mil-spec in rifles. Mil spec is completely suitable for millions of people and is the most affordable, high-quality option. CMMG makes an excellent mil spec kit that features the standard A2 grip.
Mil spec is the base layer, you can also go better. Attached to that better kit, of course, will be a higher price. AR-15LowerReceivers.com offers a premium lower parts kit that changes things up a bit. It uses a Magpul grip and trigger guard. You also get an ambidextrous safety, and premium made lower parts.
What’s Your Gun’s Purpose
What is the overall purpose of your rifle? If you are building a basic carbine as a general purpose hunting, self-defense, or plinking rifle, a mil spec lower parts kit may work perfectly for you. If you are wanting to build a special purpose rifle built for accuracy you may need something more. Most of the lower parts here aren’t that important for accuracy, what is important is the trigger. A gun built for accuracy will need an excellent trigger. This is where polished match grade triggers and self-contained units excel.
If you are building a rifle chambered in a caliber like 7.62 x 39 you may want to upgrade the trigger springs. That old AK ammo often has hard primers and needs stronger trigger springs to reliably dent the primer.
If you want a full on tactical rifle you may want to upgrade to bigger controls. This includes extended magazine release buttons, bigger safety selector, and an extended bolt release, all of this allows you to work faster.
Special Needs For Your Rifle
Do you have special needs for your rifle? If you are a left handed shooter you may find the stock configuration of an AR-15 is not very friendly. So the use of an ambidextrous safety is important to you. The same goes for something like a bad lever from Magpul as your bolt release. Always identify the special needs you may have from your rifle.
The vast majority of controls on an AR-15 are in the lower parts kit. This is where you’ll acknowledge certain unique needs you may have. Another example is in places with cold weather. Shooters using gloves may need a bigger trigger guard, and thinner grip to accommodate gloves.
If you have a particular need there is likely an accommodation out there for you.
A Complete Lower Parts Kit or Bare Minimum Parts Kit?
A bare minimum lower parts kit will include a grip, fire controls group, and the all the small pins, springs and screws. These kits allow the user to choose a stock and buffer tube of their own choosing. For example, I like the B5 stock, so I may buy a CMMG LPK and opt for a separate B5 stock and buffer assembly.
If you’d rather have an all in one complete kit these are viable and available. Complete kits will include the basics in the bare minimum kit, and a stock, buffer tube, buffer, and buffer spring. This is often the easiest way to save money. You can save even more money by throwing in a receiver as well, and just buying everything together. An 80 percent lower receiver, and complete lower parts kit like the one here can be shipped to your door without an FFL.
Unfortunately, due to California laws you have to order kits that will make your rifle California compliant. This means the kit will include a bullet button. The good news is that California compliant lower parts kits are available! Quite widely as well, in pretty much every configuration you can imagine. Even complete lower assemblies come with 80 percent lowers and California compliant lower parts kits.
You’ll also be limited to a ten round magazine, so keep that in mind when ordering some mags to really complete things.
At the end of the day, the biggest thing to remember is what do you need. Ask yourself the real questions, and be honest with yourself.